Field of the Invention
This invention generally relates to a bicycle transmission device.
Background Information
Generally, a bicycle transmission device transmits a pedaling force of the rider or an output of a motor to rotate a wheel. One example of a bicycle transmission device is described in Japanese Patent No. 5,523,636. The bicycle transmission device of this patent has a transmission mechanism that can reduce the speed of the rotation input to the crankshaft and output this to the output part, as well as a switching mechanism for switching between a state in which the crankshaft and the output part are coupled and a state in which the coupling between the crankshaft and the output part is released. When the switching mechanism is in a state in which the crankshaft and the output part are released, the rotation that is input to the crankshaft is decelerated by the transmission mechanism and is output to the output part. When the switching mechanism is in a state in which the crankshaft and the output part are coupled, the rotation that is input to the crankshaft is output to the output part without being decelerated by the transmission mechanism. That is, the transmission mechanism is able to obtain two transmission ratios with the switching mechanism.